Pop -> dead
 

Yep, my iMac G4 1.25Ghz just made a large pop sound
then went black
yep, she's not starting back up thats for sure
Well now im back on my Old iMac G3, which is actually running pretty fast on 10.3

Well, does anyone have an idea what could have happend to it?
I pulled the G4's butt off, and it i think the burning smell smells like its comming from the top part.

uhh. is it worth trying to fix?
if i take it into an apple store will they make me pay for a repair appraisal?

thanks

It could possibly be the power supply, which wouldn't be that hard to fix I imagine. Could you tell us if there is any power at all? You know, any fans wiring, any lights blinking, anything that might make you think there is any power at all?

I don't know what they may charge you to diagnose the problem; one wouldn't expect it to be a large amount. But whatever it turns out to be, it's likely they are the only ones who will be able to make the repairs, since iMac parts aren't stock parts that just any old computer shop is likely to have. If it's a problem with the logic board instead of the power supply, and I wouldn't bet against that, you might start considering whether it is economical to have the motherboard replaced, or consider a new iMac. A new logic board is likely to be about two-thirds of the cost of a new iMac. If it IS a power supply problem, and that is certainly possible, that cost should be considerably less.

Joe VanZandt

A large 'pop' not accompaned by a sizzle or sparks is sometimes a capacitor. Open it up and see if any of the larger components look damaged (small, surface-mount parts don't make much noise when they blow). The larger discrete parts are usually fairly common and easy to replace if you are good at soldering.

oh yea, sorry.
There is absolutly NO POWER whatsoever. No lights, no fans, no reaction when i press the power button.
It did sound quite a bit like a capasitor blowing, but there wasnt any sizzleing.
humm.

When i opened up the bottom of the imac, i inspected all of the parts allong that bottom shelf, and they all looked fine. I didnt go deap enough to pulling the drives out.

Does anyone know about the construction of my iMac G4?
Is that large Panel at on the bottom shelf the logic board?

I've been googleing
"iMac G4 1.25ghz Part diagram"
but no luck
What parts are on that top part? Im sure the Hard drive, and the CD drive, but what else could be up there thats blown? What capasitors would be up there?

is there any chance the power unit is up there?
That would actually make a whole lot of sense, because my computer has been having trouble staying a sleep and all that.
Isnt the sleeping directly related to this power supply unit ?

I think the power supply is a very likely suspect at this point. I only wish I knew of some place that might have the schematics so we could know for sure.

In the end though, you still have to go through a Mac store to get it fixed, they will be the only people with the right part.

My G4 Sawtooth is dead?
 

Hi all. My G4 sawtooth decided not to play this morning.

It powers up. Green light on the power switch, but there is nothing else. I don't get to hear the "Bong" sound on startup. And there's a low continual noise coming out of the front built-in speaker.

There's a red light on the mobo.

I have tried taking out the PRAM battery for an hour and it is still the same.

Could it be a shorting hard drive / cd-rom problem?

Anyone got any ideas where to go from here or what could be the problem?

I'm on a very tight budget as I'm unemployed right now.

Thanks for any help guys.

Cookie.

Sounds like a powersupply, I had a G4 iMac fail a powersupply about a month ago. It made a horrible crackling noise which I first thought was a bad fan.

You take off the first metal plate and there are 4 screws (torx) and you then take those out. The whole bottom plate comes off. Unhook all the wires from the main logic board to the rest of the unit. There will be some screws up near where the optical drive tray opens, and others along the side. Once they are removed the whole drive rack slides right out which has both the HD and the optical drive on it. You will now see two black pieces of plastic on either side of the only fan at the top of the case. Those two pieces are actually one part, and that is the powersupply. Overall, it is not too hard to get to, but not the easiest thing either. It is easy for me because I have been taking apart macs for years now and can basically take them apart now with out any hassle.

For the record, this has little or nothing to do with the original post. It would serve you much better if you were to create a new post devoted to this specific problem.

My only idea is that something in you computer is not seated correctly. I had that same thing happen once and it turned out my Airport Extreme was not seated correctly. So, you might try opening her up and making sure all of your peripherals are properly seated.

Is this the iMac with the half-sphere base? If so, do a google search with this string:

"neck spoke retainer"

That will bring up some service manuals. You'll have to figure out which one is for the 1.25 GHz model. Maybe it's the USB2 version of that iMac line?

Not exactly schematics, but the troubleshooting process gives information on what voltages, etc., should be at various points. I'd start with the "No Power" section.

Good luck--and be careful. If you don't fully understand what you're doing, it's best to leave these matters to professionals. And as Zalister says, even if you do figure out what the problem is, you may well still need an Apple authorized dealer/service operation to order you just the right parts for you.

i've done a little bit of mac hardware
i swaped the HD out of my old iMac DV G3 and that all went fine

I think i found the correct parts on this website
I couldnt find anything that said 17" 1.25ghz iMac G4 and i emailed the website owner.
They told me that this was the part i needed
http://www.mac-pro.com/s.nl/it.A/id....&category=3385
it says 20" though...
does anyone know anything about this?

I'd just email him again and make sure he checks the part number between the two. If the part number is the same, then it's a go.

That 20" model has a 190W power supply, probably to help drive the larger screen. The 17" has a 160W power supply.

http://developer.apple.com/documenta...Nov03/iMac.pdf (see p. 13)

Although I've successfully used power supplies with higher capacities than the original equipment, I'd shop around more to get the exact part if you can.

if you post the serial number I can look up the exact part number for you

hey that would be awesome

Serial Number:
W8422077QB7

iMac (usb 2.0)

part number: 922-5796

cost: 59 USD (note retailers will mark it up)

says it is instock

ok, so i pulled my computer apart.
and it was indeed the powersupply! thats good
Next step is ordering the part number tlarkin gave me
thanks for the help

check out the pictures i took
http://i179.photobucket.com/albums/w...uako/board.jpg
http://i179.photobucket.com/albums/w319/squako/zoom.jpg

It definitely blew some flame or something
http://i179.photobucket.com/albums/w...uako/blast.jpg

hey were did you look up the Power supply part number from a serial code tlarkin?
do you know where i can buy it from for the best price?

That looks like a voltage regulator.

I hold some apple certs giving me access to their internal service system, so I did a parts query for that serial number. Any AASP can directly sell you the part. They will probably have to order it, since no one carrys stock factory parts really.

If you are near a

compusa
frys
microcenter
apple store

I think they are all AASPs

I think what blew on your PSU is what is called a MOSFET chip. Which means it did its job. They are designed to blow first to save the rest of the system if failure occurs, ie so everything doesn't fry.

http://www.physorg.com/news3711.html

i ordered part number 922-5796 from mac-pro.com
and the part i got in the mail says 190W
while the one i pulled out of my computer says 160W

whats the deal? will this part still work?

the serial number you gave me matches that part number exactly. Typically they no longer produce the 160w so if you replace the part you get upgraded. This is typical for lots of parts on lots of systems across every platform. For example some of our HPs at work were shipped with a 30gig HD. Well, HP no longer carries 30 gig, so when I order a replacement under warranty I get a 40 or a 60 gig sometimes now instead. They no longer stock the lower wattage PSU because there is no need to, because the 190w probably works in all models and supplies enough power to the larger screen imac.

It should work.

yea, well it does say
"MAXIMUM OUTPUT POWER"
that definitely infers that in can be less

i installed the new power supply
and so far
everything appears to be working perfectly

its so nice to have my 17" screen back
thats what i notice most
much better resolution also it appears

thanks for all the input everyone